Patent application title: METHOD AND APPARATUS FOR TRANSMITTING HARQ-ACK FEEDBACK INFORMATION BY A USER EQUIPMENT IN A WIRELESS COMMUNICATION SYSTEM
Inventors:
IPC8 Class: AH04L118FI
USPC Class:
1 1
Class name:
Publication date: 2017-06-08
Patent application number: 20170163389
Abstract:
A method, terminal, and base station for transmitting or receiving hybrid
automatic repeat request acknowledgment (HARQ-ACK) information in a
wireless communication system. The method includes receiving, from a base
station (BS), first data on a first component carrier (CC) configured
with frequency division duplex (FDD) and second data on a second CC
configured with time division duplex (TDD), wherein one of the first and
second CC is a primary CC (PCC) and another of the first and second CC is
a secondary CC (SCC); determining HARQ-ACK timing for the first data
based on a configuration of the PCC; determining HARQ-ACK timing for the
second data based on the configuration of the PCC; transmitting, to the
BS on the PCC, HARQ-ACK information for the first data using the
determined HARQ-ACK timing for the first data and HARQ-ACK information
for the second data using the determined HARQ-ACK timing for the second
data.Claims:
1. A method for transmitting hybrid automatic repeat request
acknowledgment (HARQ-ACK) information by a terminal in a wireless
communication system, the method comprising: receiving, from a base
station (BS), first data on a first component carrier (CC) configured
with a frequency division duplex (FDD) and second data on a second CC
configured with a time division duplex (TDD), wherein one of the first CC
and the second CC is a primary CC (PCC) and another of the first CC and
the second CC is a secondary CC (SCC); determining a HARQ-ACK timing for
the first data based on a configuration of the PCC; determining a
HARQ-ACK timing for the second data based on the configuration of the
PCC; transmitting, to the BS on the PCC, HARQ-ACK information for the
first data using the determined HARQ-ACK timing for the first data and
HARQ-ACK information for the second data using the determined HARQ-ACK
timing for the second data.
2. The method of claim 1, wherein the first CC is the PCC, the HARQ-ACK timing for the first data is determined based on an FDD HARQ-ACK timing, the HARQ-ACK timing for the second data is determined based on the FDD HARQ-ACK timing, and the HARQ-ACK information for the first data and the HARQ-ACK information for the second data is transmitted on the first CC using the determined HARQ-ACK timing for the first data and the determined HARQ-ACK timing for the second data, respectively.
3. The method of claim 2, wherein the HARQ-ACK information for the first data is transmitted after four subframes later from a subframe when the first data is received, and the HARQ-ACK information for the second data is transmitted after four subframes later from a subframe when the second data is received.
4. The method of claim 1, wherein the second CC is the PCC, the HARQ-ACK timing for the first data is determined based on a TDD HARQ-ACK timing, the HARQ-ACK timing for the second data is determined based on the TDD HARQ-ACK timing, and the HARQ-ACK information for the first data and the HARQ-ACK information for the second data is transmitted on the second CC using the determined HARQ-ACK timing for the first data and the determined HARQ-ACK timing for the second data, respectively.
5. The method of claim 4, wherein the TDD HARQ-ACK timing is determined based on an uplink(UL)/downlink(DL) configuration of the second CC.
6. A method for receiving hybrid automatic repeat request acknowledgment (HARQ-ACK) information by a base station (BS) in a wireless communication system, the method comprising: transmitting, to a terminal, first data on a first component carrier (CC) configured with a frequency division duplex (FDD) and second data on a second CC configured with a time division duplex (TDD), wherein one of the first CC and the second CC is a primary CC (PCC) and another of the first CC and the second CC is a secondary CC (SCC); and receiving, from the terminal on the PCC, HARQ-ACK information for the first data with a HARQ-ACK timing for the first data and HARQ-ACK information for the second data with a HARQ-ACK timing for the first data, wherein the HARQ-ACK timing for the first data and the HARQ-ACK timing for the second data are determined based on a configuration of the PCC.
7. The method of claim 6, wherein the first CC is the PCC, the HARQ-ACK timing for the first data is determined based on an FDD HARQ-ACK timing, the HARQ-ACK timing for the second data is determined based on the FDD HARQ-ACK timing, and the HARQ-ACK information for the first data and the HARQ-ACK information for the second data is received on the first CC with the determined HARQ-ACK timing for the first data and the determined HARQ-ACK timing for the second data, respectively.
8. The method of claim 7, wherein the HARQ-ACK information for the first data is received after four subframes later from a subframe when the first data is received, and the HARQ-ACK information for the second data is received after four subframes later from a subframe when the second data is received.
9. The method of claim 6, wherein the second CC is the PCC, the HARQ-ACK timing for the first data is determined based on a TDD HARQ-ACK timing, the HARQ-ACK timing for the second data is determined based on the TDD HARQ-ACK timing, and the HARQ-ACK information for the first data and the HARQ-ACK information for the second data is received on the second CC with the determined HARQ-ACK timing for the first data and the determined HARQ-ACK timing for the second data, respectively.
10. The method of claim 9, wherein the TDD HARQ-ACK timing is determined based on an uplink(UL)/downlink(DL) configuration of the second CC.
11. A terminal for transmitting hybrid automatic repeat request acknowledgment (HARQ-ACK) information in a wireless communication system, the terminal comprising: a transceiver; and a controller coupled to the transceiver, wherein the controller is configured to: receive, from a base station (BS), first data on a first component carrier (CC) configured with a frequency division duplex (FDD) and second data on a second CC configured with a time division duplex (TDD), wherein one of the first CC and the second CC is a primary CC (PCC) and another of the first CC and the second CC is a secondary CC (SCC); determine a HARQ-ACK timing for the first data based on a configuration of the PCC; determine a HARQ-ACK timing for the second data based on the configuration of the PCC; transmit, to the BS on the PCC, HARQ-ACK information for the first data using the determined HARQ-ACK timing for the first data and HARQ-ACK information for the second data using the determined HARQ-ACK timing for the second data.
12. The terminal of claim 11, wherein the first CC is the PCC, the HARQ-ACK timing for the first data is determined based on an FDD HARQ-ACK timing, the HARQ-ACK timing for the second data is determined based on the FDD HARQ-ACK timing, and the HARQ-ACK information for the first data and the HARQ-ACK information for the second data is transmitted on the first CC using the determined HARQ-ACK timing for the first data and the determined HARQ-ACK timing for the second data, respectively.
13. The terminal of claim 12, wherein the HARQ-ACK information for the first data is transmitted after four subframes later from a subframe when the first data is received, and the HARQ-ACK information for the second data is transmitted after four subframes later from a subframe when the second data is received.
14. The terminal of claim 11, wherein the second CC is the PCC, the HARQ-ACK timing for the first data is determined based on a TDD HARQ-ACK timing, the HARQ-ACK timing for the second data is determined based on the TDD HARQ-ACK timing, and the HARQ-ACK information for the first data and the HARQ-ACK information for the second data is transmitted on the second CC using the determined HARQ-ACK timing for the first data and the determined HARQ-ACK timing for the second data, respectively.
15. The terminal of claim 14, wherein the TDD HARQ-ACK timing is determined based on an uplink(UL)/downlink(DL) configuration of the second CC.
16. A base station (BS) for receiving hybrid automatic repeat request acknowledgment (HARQ-ACK) information in a wireless communication system, the BS comprising: a transceiver; and a controller coupled to the transceiver, wherein the controller is configured to: transmit, to a terminal, first data on a first component carrier (CC) configured with a frequency division duplex (FDD) and second data on a second CC configured with a time division duplex (TDD), wherein one of the first CC and the second CC is a primary CC (PCC) and another of the first CC and the second CC is a secondary CC (SCC); and receive, from the terminal on the PCC, HARQ-ACK information for the first data with a HARQ-ACK timing for the first data and HARQ-ACK information for the second data with a HARQ-ACK timing for the first data, wherein each of the HARQ-ACK timing for the first data and the HARQ-ACK timing for the second data is determined based on a configuration of the PCC.
17. The BS of claim 16, wherein the first CC is the PCC, the HARQ-ACK timing for the first data is determined based on an FDD HARQ-ACK timing, the HARQ-ACK timing for the second data is determined based on the FDD HARQ-ACK timing, and the HARQ-ACK information for the first data and the HARQ-ACK information for the second data is received on the first CC with the determined HARQ-ACK timing for the first data and the determined HARQ-ACK timing for the second data, respectively.
18. The BS of claim 17, wherein the HARQ-ACK information for the first data is received after four subframes later from a subframe when the first data is received, and the HARQ-ACK information for the second data is received after four subframes later from a subframe when the second data is received.
19. The BS of claim 16, wherein the second CC is the PCC, the HARQ-ACK timing for the first data is determined based on a TDD HARQ-ACK timing, the HARQ-ACK timing for the second data is determined based on the TDD HARQ-ACK timing, and the HARQ-ACK information for the first data and the HARQ-ACK information for the second data is received on the second CC with the determined HARQ-ACK timing for the first data and the determined HARQ-ACK timing for the second data, respectively.
20. The BS of claim 19, wherein the TDD HARQ-ACK timing is determined based on an uplink(UL)/downlink(DL) configuration of the second CC.
Description:
PRIORITY
[0001] This patent application is a Continuation Application of U.S. patent application Ser. No. 13/945,601, filed in the United States Patent and Trademark Office on Jul. 18, 2013, which claims priority under 35 U.S.C. .sctn.119(a) to Chinese Patent Application Serial No. 201210249342.8, which was filed in the Chinese Patent Office on Jul. 18, 2012, the entire content of each of which are hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present disclosure relates generally to radio communication system technologies, and more particularly, to a method and apparatus for transmitting Hybrid Automatic Repeat reQuest ACKnowledgment (HARQ-ACK) feedback information.
[0004] 2. Description of the Related Art
[0005] A Long Term Evolution (LTE) system supports two duplexing modes, i.e., Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD).
[0006] FIG. 1 illustrates a frame structure of a conventional TDD system.
[0007] Referring to FIG. 1, a length of each radio frame is 10 ms, and each radio frame is divided into two 5 ms half-frames. Each half-frame includes eight 0.5 ms time slots and three special fields, i.e., a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP), and an Uplink Pilot Time Slot (UpPTS). The total length of the three special fields is 1 ms.
[0008] Each subframe includes two consecutive time slots. For example, a frame k includes slot 2k and slot 2k+1.
[0009] The TDD system supports seven TDD uplink/downlink configurations, as shown in Table 1 below. In Table 1, D denotes a downlink subframe, U denotes an uplink subframe, and S denotes a special subframe with the above-mentioned three special fields.
TABLE-US-00001 TABLE 1 Index number of Switching config- point index of subframe uration period 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U D S U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D D D D 6 10 ms D S U U U D S U U D
[0010] To improve a user transmission rate, an LTE-Advanced (LTE-A) system has been proposed. In LTE-A, multiple Component Carriers (CCs) are aggregated to obtain greater bandwidth, i.e., Carrier Aggregation (CA), which constitutes a downlink and an uplink of a communication system to support a higher transmission rate. For example, a 100 MHz bandwidth may be achieved by aggregating five 20 MHz CCs. Herein, each CC may be referred to as a Cell.
[0011] A Base Station (BS) may configure a User Equipment (UE) to work in multiple CCs, one of which is a primary CC (PCC or Pcell), while any other CCs are a secondary CC (SCC or Scell).
[0012] In the LTE-A system, all of the CCs aggregated together are configured with an FDD configuration or are all configured with a TDD configuration.
[0013] However, to further improve a user transmission rate, subsequent research is being performed on LTE-A in the hopes of determining a method to effectively support a CC configured with a TDD configuration and a CC configured with a FDD configuration to perform carrier aggregation. For example, when carrier aggregation includes a CC configured with a TDD configuration and a CC configured with a FDD configuration, the is no current way for a UE to determine a HARQ-ACK timing for transmitting HARQ-ACK.
SUMMARY OF THE INVENTION
[0014] Accordingly, the present invention is designed to address at least the problems and/or disadvantages described above and to provide at least the advantages described below.
[0015] An aspect of the present invention is to provide a method and an apparatus for transmitting HARQ-ACK feedback information, which can effectively achieve HARQ-ACK information transmission when a TDD CC and an FDD CC are aggregated.
[0016] In accordance with an aspect of the present invention, a method is provided for transmitting hybrid automatic repeat request acknowledgment (HARQ-ACK) information by a terminal in a wireless communication system. The method includes receiving, from a base station (BS), first data on a first component carrier (CC) configured with a frequency division duplex (FDD) and second data on a second CC configured with a time division duplex (TDD), wherein one of the first CC and the second CC is a primary CC (PCC) and another of the first CC and the second CC is a secondary CC (SCC); determining a HARQ-ACK timing for the first data based on a configuration of the PCC; determining a HARQ-ACK timing for the second data based on the configuration of the PCC; transmitting, to the BS on the PCC, HARQ-ACK information for the first data using the determined HARQ-ACK timing for the first data and HARQ-ACK information for the second data using the determined HARQ-ACK timing for the second data.
[0017] In accordance with another aspect of the present invention, a method for receiving hybrid automatic repeat request acknowledgment (HARQ-ACK) information by a base station (BS) in a wireless communication system is provided. The method includes transmitting, to a terminal, first data on a first component carrier (CC) configured with a frequency division duplex (FDD) and second data on a second CC configured with a time division duplex (TDD), wherein one of the first CC and the second CC is a primary CC (PCC) and another of the first CC and the second CC is a secondary CC (SCC); and receiving, from the terminal on the PCC, HARQ-ACK information for the first data with a HARQ-ACK timing for the first data and HARQ-ACK information for the second data with a HARQ-ACK timing for the first data, wherein the HARQ-ACK timing for the first data and the HARQ-ACK timing for the second data are determined based on a configuration of the PCC.
[0018] In accordance with another aspect of the present invention, a terminal for transmitting hybrid automatic repeat request acknowledgment (HARQ-ACK) information in a wireless communication system is provided. The terminal includes a transceiver; and a controller coupled to the transceiver, wherein the controller is configured to: receive, from a base station (BS), first data on a first component carrier (CC) configured with a frequency division duplex (FDD) and second data on a second CC configured with a time division duplex (TDD), wherein one of the first CC and the second CC is a primary CC (PCC) and another of the first CC and the second CC is a secondary CC (SCC); determine a HARQ-ACK timing for the first data based on a configuration of the PCC; determine a HARQ-ACK timing for the second data based on the configuration of the PCC; transmit, to the BS on the PCC, HARQ-ACK information for the first data using the determined HARQ-ACK timing for the first data and HARQ-ACK information for the second data using the determined HARQ-ACK timing for the second data.
[0019] In accordance with another aspect of the present invention, a base station (BS) for receiving hybrid automatic repeat request acknowledgment (HARQ-ACK) information in a wireless communication system is provided. The BS includes a transceiver; and a controller coupled to the transceiver, wherein the controller is configured to: transmit, to a terminal, first data on a first component carrier (CC) configured with a frequency division duplex (FDD) and second data on a second CC configured with a time division duplex (TDD), wherein one of the first CC and the second CC is a primary CC (PCC) and another of the first CC and the second CC is a secondary CC (SCC); and receive, from the terminal on the PCC, HARQ-ACK information for the first data with a HARQ-ACK timing for the first data and HARQ-ACK information for the second data with a HARQ-ACK timing for the first data, wherein each of the HARQ-ACK timing for the first data and the HARQ-ACK timing for the second data is determined based on a configuration of the PCC.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The above and other aspects, features, and advantages of certain embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
[0021] FIG. 1 illustrates a frame structure in a conventional TDD system;
[0022] FIG. 2 is a flowchart illustrating a method for transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention;
[0023] FIG. 3 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention;
[0024] FIG. 4 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention;
[0025] FIG. 5 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention;
[0026] FIG. 6 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention;
[0027] FIG. 7 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention;
[0028] FIG. 8 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention;
[0029] FIG. 9 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention; and
[0030] FIG. 10 is a block diagram illustrating a UE according to an embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0031] Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, specific details such as detailed configuration and components are merely provided to assist the overall understanding of these embodiments of the present invention. Therefore, it should be apparent to those skilled in the art that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[0032] For a TDD uplink/downlink configuration, according to a ratio of downlink subframes and uplink subframes, HARQ-ACK feedback information of a downlink transmission within zero, i.e., no HARQ-ACK feedback information is transmitted in the uplink subframe, at least one downlink subframe may be transmitted in one uplink subframe. The zero downlink subframes for which the HARQ-ACK feedback information is transmitted within a same uplink subframe is referred to as "a bundling window" corresponding to the uplink subframe. Accordingly, the number of the downlink subframes included in the bundling window referred to as the size of the bundling window.
[0033] For a UE of a CA system configured with a TDD CC and an FDD CC, it is assumed herein that CCs configured for the UE include at least one FDD CC and at least one TDD CC.
[0034] FIG. 2 is a flowchart illustrating a method for transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention.
[0035] Referring to FIG. 2, in step 201, a UE determines a HARQ-ACK timing and a CC transmitting HARQ-ACK feedback information, based on a composition structure of CCs configured for the UE.
[0036] In step 202, the UE transmits the HARQ-ACK feedback information on a PUCCH or a PUSCH of the determined CC, based on the determined HARQ-ACK timing.
[0037] In accordance with an embodiment of the present invention, CCs configured for a UE are grouped into two groups, i.e., all CCs configured with an FDD configuration are grouped into one group, and all CCs configured with a TDD configuration are grouped into the other group. All of the CCs in the group with the FDD configuration follow an FDD HARQ-ACK timing, and all HARQ-ACK information of the group is transmitted on the PCC. For each of the CCs in the group with the TDD configuration, a HARQ-ACK timing is determined according to TDD uplink/downlink configurations of the CCs in the group (as shown in Table 1 above), and all HARQ-ACK information of the group with TDD configuration is transmitted on a specific CC determined from the TDD CCs.
[0038] RRC signaling may be used to indicate which CC is used for transmitting the HARQ-ACK information among the CCs in the group with TDD configuration. The indicated CC is commonly referred to as a second PCC.
[0039] FIG. 3 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention. In FIG. 3, it is assumed that a BS configures two CCs for a CA UE, i.e., a PCC and an SCC.
[0040] Referring to FIG. 3, the PCC is configured with an FDD configuration, and the SCC is configured with TDD uplink/downlink configuration 2. In this combination, the PCC follows an FDD HARQ-ACK timing, and HARQ-ACK information of the PCC is transmitted on the PCC. The SCC follows a HARQ-ACK timing of TDD uplink/downlink configuration 2, and HARQ-ACK information of the SCC is transmitted on the SCC.
[0041] In accordance with an embodiment of the present invention, CCs configured for the UE are grouped into two groups, i.e., all of the CCs configured with an FDD configuration are grouped into one group, and all of the CCs configured with a TDD configuration are grouped into the other group. All of the CCs in the group with the FDD configuration follow an FDD HARQ-ACK timing, and HARQ-ACK information of the group is transmitted on the PCC. The CCs in the group with the TDD configuration determine a HARQ-ACK timing for each CC according to TDD uplink/downlink configurations of the CCs in the group, and HARQ-ACK information of the group with TDD configuration is transmitted on the FDD PCC.
[0042] FIG. 4 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention. In FIG. 4, it is assumed that a BS configures two CCs for a CA UE, i.e., a PCC and an SCC.
[0043] Referring to FIG. 4, the PCC is configured with an FDD configuration, and the SCC is configured with TDD uplink/downlink configuration 2. In this combination, the PCC follows an FDD HARQ-ACK timing, and HARQ-ACK information of the PCC is transmitted on the PCC. The SCC follows a HARQ-ACK timing of TDD uplink/downlink configuration 2, and HARQ-ACK information of the SCC is transmitted on the FDD PCC.
[0044] In accordance with an embodiment of the present invention, all CCs configured for the UE follow an FDD HARQ-ACK timing, and all HARQ-ACK information is transmitted on the FDD PCC. Specifically, an FDD CC follows the FDD HARQ-ACK timing. For a TDD CC, a HARQ-ACK timing of a TDD downlink subframe is determined according to a HARQ-ACK timing of an FDD downlink subframe that is on the same subframe timing as the TDD downlink subframe. HARQ-ACK information of all of the CCs is transmitted on the FDD PCC. In this method, timing of all of the CCs is consistent, and HARQ-ACK information of all of the CCs is transmitted on the PCC, so that the implementation complexity is lower compared with the methods illustrated in FIGS. 3 and 4.
[0045] FIG. 5 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention. In FIG. 5, it is assumed that a BS configures two CCs for a CA UE, i.e., a PCC and an SCC.
[0046] Referring to FIG. 5, the PCC is configured with an FDD configuration, and the SCC is configured with TDD uplink/downlink configuration 2. In this combination, the PCC follows an FDD HARQ-ACK timing, and HARQ-ACK information of the PCC is transmitted on the PCC. The SCC follows the FDD HARQ-ACK timing, and HARQ-ACK information of the SCC is transmitted on the PCC.
[0047] In accordance with an embodiment of the present invention, CCs configured for the UE are grouped into two groups, i.e., all of the CCs configured with an FDD configuration are grouped into one group, and all of the CCs configured with a TDD configuration are grouped into the other group. All of the CCs in the group with the FDD configuration follow an FDD HARQ-ACK timing, and HARQ-ACK information of the group is transmitted on a specific FDD PCC. For each CC in the group with the TDD configuration, a HARQ-ACK timing is determined according to TDD uplink/downlink configurations of the CCs in the group, and HARQ-ACK information of the group with the TDD configuration is transmitted on the PCC.
[0048] FIG. 6 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention. In FIG. 6, it is assumed that a BS configures two CCs for a CA UE, i.e., a PCC and an SCC.
[0049] Referring to FIG. 6, the PCC is configured with TDD uplink/downlink configuration 2, and the SCC is configured with an FDD configuration. In this combination, the PCC follows a HARQ-ACK timing of TDD uplink/downlink configuration 2, and HARQ-ACK information of the PCC is transmitted on the PCC. The SCC follows an FDD HARQ-ACK timing relationship, and HARQ-ACK information of the SCC is transmitted on the SCC.
[0050] In accordance with an embodiment of the present invention, CCs configured for the UE are grouped into two groups, i.e., all of the CCs configured with an FDD configuration are grouped into one group, and all of the CCs configured with a TDD configuration are grouped into the other group. All of the CCs in the group with the FDD configuration follow an FDD HARQ-ACK timing. When the PCC is an uplink subframe, HARQ-ACK information of the group with the FDD configuration is transmitted on the PCC. When the PCC is a downlink subframe, the HARQ-ACK information of the group with the FDD configuration is transmitted on a specific FDD CC. For each CC in the group with the TDD configuration a HARQ-ACK timing is determined according to TDD uplink/downlink configurations of the CCs in the group, and HARQ-ACK information of the group with the TDD configuration is transmitted on the PCC. As described above, HARQ-ACK information of each CC is transmitted through the PCC as much as possible, thus it is consistent with previous HARQ-ACK transmission modes. When the PCC is a downlink subframe and cannot transmit HARQ-ACK information, the HARQ-ACK information is transmitted through an FDD CC.
[0051] Again, RRC signaling may be used to indicate which CC is used for transmitting the HARQ-ACK information among the CCs in the group with FDD configuration. The indicated CC is called a second PCC.
[0052] FIG. 7 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention. In FIG. 7, it is assumed that a BS configures two CCs for a CA UE, i.e., a PCC and an SCC.
[0053] Referring to FIG. 7, the PCC is configured with TDD uplink/downlink configuration 2, and the SCC is configured with an FDD configuration. In this combination, the PCC follows a HARQ-ACK timing of the TDD uplink/downlink configuration 2, and HARQ-ACK information of the PCC is transmitted on the PCC. The SCC follows an FDD HARQ-ACK timing, HARQ-ACK information of the SCC is transmitted on the PCC in subframe 2 or subframe 7, and the HARQ-ACK information of the SCC is transmitted on the SCC in subframes 0, 1, 3, 4, 5, 6, 8, or 9.
[0054] In accordance with an embodiment of the present invention, CCs configured for the UE are grouped into two groups, i.e., all of the CCs configured with an FDD configuration are grouped into one group, and all of the CCs configured with a TDD configuration are grouped into the other group. All FDD CCs follow a HARQ-ACK timing of the PCC. However, for each CC in the group with the TDD configuration, HARQ-ACK timing is determined according to the TDD uplink/downlink configurations of the CCs in the group. HARQ-ACK information of all of the CCs is transmitted on the PCC.
[0055] Specifically, for a downlink subframe of an FDD CC, if the PCC is a downlink subframe on the same subframe timing, a HARQ-ACK timing of the FDD downlink subframe is determined according to a HARQ-ACK timing of the downlink subframe of the PCC on the same subframe. For the downlink subframe of the FDD CC, if the PCC is an uplink subframe on the same subframe timing, there is not a corresponding uplink subframe used for transmitting the HARQ-ACK information on the same subframe in accordance with a HARQ-ACK timing of the PCC, then the FDD subframe could not transmit downlink data. For each CC in the group with TDD configuration a HARQ-ACK timing is determined according to a TDD uplink/downlink configuration of each CC in the group. HARQ-ACK information of all of the CCs is transmitted on the PCC. Herein, HARQ-ACK timing of all of the CCs is consistent, and HARQ-ACK of all of the CCs is transmitted on the PCC, so that the implementation complexity is lower compared with the methods illustrates in FIGS. 6 and 7. However, part of downlink subframes may not be able to transmit downlink data on the FDD CC, which results in waste of downlink resources.
[0056] FIG. 8 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention. In FIG. 8, it is assumed that a BS configures two CCs for a CA UE, i.e., a PCC and an SCC.
[0057] Referring to FIG. 8, the PCC is configured with TDD uplink/downlink configuration 2, and the SCC is configured with an FDD configuration. In this combination, the PCC follows a HARQ-ACK timing of TDD uplink/downlink configuration 2, and HARQ-ACK information of the PCC is transmitted on the PCC. The SCC follows the HARQ-ACK timing of the TDD uplink/downlink configuration 2, HARQ-ACK information of downlink subframes 4, 5, 6, and 8 of radio frame n is transmitted on uplink subframe 2 of radio frame n+1 of the PCC, and HARQ-ACK information of downlink subframe 9 of radio frame n and HARQ-ACK information of downlink subframes 0, 1, and 3 of radio frame n+1 are transmitted on uplink subframe 7 of radio frame n+1 of the PCC. For the SCC and downlink subframes 2 and 7 of radio frame n, subframes 2 and 7 of the PCC are all uplink subframes, therefore, downlink subframes 2 and 7 of the SCC do not transmit downlink data.
[0058] In accordance with an embodiment of the present invention, for each CC in the group with TDD configuration, a HARQ-ACK timing is determined according to TDD uplink/downlink configurations of the CCs in the group, and HARQ-ACK information of the PCC is transmitted on the PCC. HARQ-ACK information of downlink subframes is distributed by FDD CCs as evenly as possible on each uplink subframe of the PCC for transmission. That is, it is ensured that the number of subframes difference among FDD HARQ-ACK information transmitted by each uplink subframe of the PCC is the smallest one.
[0059] FIG. 9 illustrates HARQ-ACK timing and a determination of a CC transmitting HARQ-ACK feedback information in accordance with an embodiment of the present invention. In FIG. 9, HARQ-ACK timing of FDD CCs are completely rearranged, but the HARQ-ACK information transmitted on each uplink subframe of the PCC is distributed more averagely. Herein, more averagely means that the number of downlink subframes on which HARQ-ACK are transmitted in one uplink subframes keeps as equal as possible for each uplink subframe. As a result, uplink resources are used fully and evenly.
[0060] Referring to FIG. 9, the PCC is configured with TDD uplink/downlink configuration 2, and the SCC is configured with an FDD configuration. In this combination, the PCC follows a HARQ-ACK timing of TDD uplink/downlink configuration 2, and HARQ-ACK information of the PCC is transmitted on the PCC. The SCC follows a new HARQ-ACK timing, so that the number of downlink subframes for which the FDD HARQ-ACK information is transmitted on uplink subframes of the PCC is more average, and the shortest duration for the UE processing data is met. Generally, the smaller a time delay between transmission of HARQ-ACK feedback of a downlink subframe and transmission of the downlink subframe is, the better. HARQ-ACK feedback information of downlink subframes 4, 5, 6, 7, and 8 of radio frame n may be transmitted on uplink subframe 2 of radio frame n+1 of the PCC, and HARQ-ACK feedback information of downlink subframe 9 of radio frame n and HARQ-ACK feedback information of downlink subframes 0, 1, 2, and 3 of radio frame n+1 may be transmitted on uplink subframe 7 of radio frame n+1 of the PCC.
[0061] The above-described methods for determining the timing and the CC transmitting the HARQ-ACK, as illustrated in FIGS. 3 to 9, are also applicable to a scenario in which HARQ-ACK information is carried through a PUSCH or a PUCCH.
[0062] In conventional systems, when HARQ-ACK information is carried through a PUSCH under a TDD configuration, if the PUSCH carrying the HARQ-ACK information is scheduled through a Physical Downlink Control CHannel (PDCCH), then the PDCCH includes an Uplink Downlink Assignment Index (UL DAI) field, which is used to indicate the number of downlink subframes corresponding to the HARQ-ACK information carried in the PUSCH. When the HARQ-ACK information is carried through the PUSCH under an FDD configuration, uplink subframes carrying the HARQ-ACK information are determined. Therefore, the PDCCH scheduling the PUSCH does not include the UL DAI field. For a CA UE simultaneously configured with the TDD and FDD configurations, the number of downlink subframes corresponding to HARQ-ACK feedback information transmitted on a current uplink subframe may be determined according to methods described below.
[0063] Specifically, if HARQ-ACK information is transmitted on a PUSCH and the PUSCH transmission is scheduled by a PDCCH that does not include a UL DAI field or the PUSCH transmission is not scheduled by a detected PDCCH, for a CC, the number of downlink subframes for which HARQ-ACK feedback information is transmitted on the PUSCH of the current uplink subframe is the size of a bundling window of the CC.
[0064] If the PUSCH transmission is scheduled by a PDCCH including the UL DAI field, then for any CC, the number of downlink subframes for which HARQ-ACK feedback information is transmitted on the PUSCH of the current uplink subframe is determined according to the size of the bundling window of the CC and the UL DAI. Particularly, the number of the downlink subframes is equal to the minimum value between the size of the bundling window and a value of the UL DAI field.
[0065] For a BS that configures two CCs for a CA UE, i.e., a PCC and an SCC, the PCC may be configured with an FDD configuration, and the SCC may be configured with TDD uplink/downlink configuration 2. In this combination, assuming that the PCC follows an FDD HARQ-ACK timing and the SCC follows the FDD HARQ-ACK timing, if a PUSCH is transmitted on the PCC and a PDCCH scheduling the PUSCH of the FDD CC does not include a UL DAI field, the number of downlink subframes corresponding to HARQ-ACK information of the FDD CC or the TDD CC is equal to the size of a bundling window of each CC. If the PUSCH is transmitted on the SCC and is scheduled by the PDCCH, and the PDCCH scheduling the PUSCH of the TDD CC includes the UL DAI field, the number of downlink subframes corresponding to HARQ-ACK information of the FDD CC and the number of downlink subframes corresponding to HARQ-ACK information of the TDD CC are respectively equal to min.{UL DAI, the size of the bundling window of the CC}.
[0066] In addition, after a HARQ-ACK timing and a CC transmitting transmission HARQ-ACK are determined, as described above, when the HARQ-ACK information is transmitted according to PUCCH format 1b for channel selection, mapping the HARQ-ACK information may be performed using a TDD table for mapping, i.e., Table 5, Table 6, or Table 7, as shown below. Another method is to use an FDD table for mapping, i.e., Table 2, Table 3, or Table 4, as shown below.
[0067] It is noted that various embodiments of the present invention described herein are not limited to the use of a channel selection mapping form, which has already existed in a conventional LTE system, and may use other channel selection mapping forms.
TABLE-US-00002 TABLE 2 HARQ- HARQ- ACK(0) ACK(1) n.sub.PUCCH.sup.(1) b(0)b(1) ACK ACK n.sub.PUCCH,1.sup.(1) 1, 1 ACK NACK/DTX n.sub.PUCCH,0.sup.(1) 1, 1 NACK/DTX ACK n.sub.PUCCH,1.sup.(1) 0, 0 NACK NACK/DTX n.sub.PUCCH,0.sup.(1) 0, 0 DTX NACK/DTX No Transmission
TABLE-US-00003 TABLE 3 HARQ- HARQ- HARQ- ACK(0) ACK(1) ACK(2) n.sub.PUCCH.sup.(1) b(0)b(1) ACK ACK ACK n.sub.PUCCH,1.sup.(1) 1, 1 ACK NACK/DTX ACK n.sub.PUCCH,1.sup.(1) 1, 0 NACK/DTX ACK ACK n.sub.PUCCH,1.sup.(1) 0, 1 NACK/DTX NACK/DTX ACK n.sub.PUCCH,2.sup.(1) 1, 1 ACK ACK NACK/DTX n.sub.PUCCH,0.sup.(1) 1, 1 ACK NACK/DTX NACK/DTX n.sub.PUCCH,0.sup.(1) 1, 0 NACK/DTX ACK NACK/DTX n.sub.PUCCH,0.sup.(1) 0, 1 NACK/DTX NACK/DTX NACK n.sub.PUCCH,2.sup.(1) 0, 0 NACK NACK/DTX DTX n.sub.PUCCH,0.sup.(1) 0, 0 NACK/DTX NACK DTX n.sub.PUCCH,0.sup.(1) 0, 0 DTX DTX DTX No Transmission
TABLE-US-00004 TABLE 4 HARQ- HARQ- HARQ-ACK(0) ACK(1) ACK(2) HARQ-ACK(3) n.sub.PUCCH.sup.(1) b(0)b(1) ACK ACK ACK ACK n.sub.PUCCH,1.sup.(1) 1, 1 ACK NACK/DTX ACK ACK n.sub.PUCCH,2.sup.(1) 0, 1 NACK/DTX ACK ACK ACK n.sub.PUCCH,1.sup.(1) 0, 1 NACK/DTX NACK/DTX ACK ACK n.sub.PUCCH,3.sup.(1) 1, 1 ACK ACK ACK NACK/DTX n.sub.PUCCH,1.sup.(1) 1, 0 ACK NACK/DTX ACK NACK/DTX n.sub.PUCCH,2.sup.(1) 0, 0 NACK/DTX ACK ACK NACK/DTX n.sub.PUCCH,1.sup.(1) 0, 0 NACK/DTX NACK/DTX ACK NACK/DTX n.sub.PUCCH,3.sup.(1) 1, 0 ACK ACK NACK/DTX ACK n.sub.PUCCH,2.sup.(1) 1, 1 ACK NACK/DTX NACK/DTX ACK n.sub.PUCCH,2.sup.(1) 1, 0 NACK/DTX ACK NACK/DTX ACK n.sub.PUCCH,3.sup.(1) 0, 1 NACK/DTX NACK/DTX NACK/DTX ACK n.sub.PUCCH,3.sup.(1) 0, 0 ACK ACK NACK/DTX NACK/DTX n.sub.PUCCH,0.sup.(1) 1, 1 ACK NACK/DTX NACK/DTX NACK/DTX n.sub.PUCCH,0.sup.(1) 1, 0 NACK/DTX ACK NACK/DTX NACK/DTX n.sub.PUCCH,0.sup.(1) 0, 1 NACK/DTX NACK NACK/DTX NACK/DTX n.sub.PUCCH,0.sup.(1) 0, 0 NACK NACK/DTX NACK/DTX NACK/DTX n.sub.PUCCH,0.sup.(1) 0, 0 DTX DTX NACK/DTX NACK/DTX No Transmission
TABLE-US-00005 TABLE 5 HARQ-ACK(0), HARQ- ACK(1) n.sub.PUCCH.sup.(1) b(0)b(1) ACK, ACK n.sub.PUCCH,1.sup.(1) 1, 0 ACK, NACK/DTX n.sub.PUCCH,0.sup.(1) 1, 1 NACK/DTX, ACK n.sub.PUCCH,1.sup.(1) 0, 1 NACK, NACK/DTX n.sub.PUCCH,0.sup.(1) 0, 0 DTX, NACK/DTX No Transmission
TABLE-US-00006 TABLE 6 HARQ-ACK(0), HARQ- ACK(1), HARQ-ACK(2) n.sub.PUCCH.sup.(1) b(0)b(1) ACK, ACK, ACK n.sub.PUCCH.sup.(1) 1, 1 ACK, ACK, NACK/DTX n.sub.PUCCH.sup.(1) 1, 0 ACK, NACK/DTX, ACK n.sub.PUCCH.sup.(1) 1, 0 ACK, NACK/DTX, n.sub.PUCCH.sup.(1) 1, 1 NACK/DTX NACK/DTX, ACK, ACK n.sub.PUCCH.sup.(1) 0, 1 NACK/DTX, ACK, n.sub.PUCCH.sup.(1) 0, 1 NACK/DTX NACK/DTX, NACK/DTX, n.sub.PUCCH.sup.(1) 0, 0 ACK NACK, NACK/DTX, n.sub.PUCCH.sup.(1) 0 0 NACK/DTX DTX, NACK/DTX, No NACK/DTX Transmission
TABLE-US-00007 TABLE 7 HARQ-ACK(0), HARQ-ACK(1), HARQ- ACK(2), HARQ-ACK(3) n.sub.PUCCH.sup.(1) b(0)b(1) ACK, ACK, ACK, ACK n.sub.PUCCH,1.sup.(1) 1, 1 ACK, ACK, ACK, NACK/DTX n.sub.PUCCH,2.sup.(1) 1, 1 ACK, ACK, NACK/DTX, ACK n.sub.PUCCH,0.sup.(1) 1, 0 ACK, ACK, NACK/DTX, NACK/DTX n.sub.PUCCH,1.sup.(1) 1, 0 ACK, NACK/DTX, ACK, ACK n.sub.PUCCH,3.sup.(1) 1, 1 ACK, NACK/DTX, ACK, NACK/DTX n.sub.PUCCH,2.sup.(1) 1, 0 ACK, NACK/DTX, NACK/DTX, ACK n.sub.PUCCH,0.sup.(1) 0, 1 ACK, NACK/DTX, NACK/DTX, NACK/DTX n.sub.PUCCH,0.sup.(1) 1, 1 NACK/DTX, ACK, ACK, ACK n.sub.PUCCH,1.sup.(1) 0, 0 NACK/DTX, ACK, ACK, NACK/DTX n.sub.PUCCH,2.sup.(1) 0, 1 NACK/DTX, ACK, NACK/DTX, ACK n.sub.PUCCH,3.sup.(1) 1, 0 NACK/DTX, ACK, NACK/DTX, NACK/DTX n.sub.PUCCH,1.sup.(1) 0, 1 NACK/DTX, NACK/DTX, ACK, ACK n.sub.PUCCH,3.sup.(1) 0, 1 NACK/DTX, NACK/DTX, ACK, NACK/DTX n.sub.PUCCH,2.sup.(1) 0, 0 NACK/DTX, NACK/DTX, NACK/DTX, ACK n.sub.PUCCH,3.sup.(1) 0, 0 NACK, NACK/DTX, NACK/DTX, NACK/DTX n.sub.PUCCH,0.sup.(1) 0, 0 DTX, NACK/DTX, NACK/DTX, NACK/DTX No Transmission
[0068] As shown above, when transmitting HARQ-ACK feedback information, wherein a CC is configured with a TDD configuration and a CC configured with an FDD configuration in a CA simultaneously, a HARQ-ACK timing and a CC transmitting HARQ-ACK feedback information are determined according to a composition structure of CCs. The HARQ-ACK feedback information is transmitted on the determined CC according to the determined HARQ-ACK timing. Therefore, HARQ-ACK information can be transmitted effectively when a CC is configured with a TDD configuration and a CC is configured with an FDD configuration, simultaneously, in CA.
[0069] FIG. 10 is a block diagram illustrating a UE according to an embodiment of the present invention.
[0070] Referring to FIG. 10, the UE includes a receiver 1000, a controller 1002, and a transmitter 1004. The UE may also include other units, e.g., a display, a keypad, etc., which are not shown here for purposes of clarity.
[0071] The receiver 1000 receives signals and data. The transmitter 1004 transmits signals, data, and HARQ-ACK feedback information. The controller 1002 controls the receiver 1000 and the transmitter 1004.
[0072] Specifically, the controller 1002 performs operations according to the above-described embodiments of the present invention. For example, the controller 1002 determines a HARQ-ACK timing and a CC for transmitting the HARQ-ACK feedback information, based on a composition structure of CCs configured for the UE, and controls to the transmitter 1004 to transmit the HARQ-ACK feedback information on a PUCCH or PUSCH of the determined CC, based on the determined HARQ-ACK timing.
[0073] While the present invention has been particularly shown and described with reference to certain embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents.
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